We stubbornly refused to deploy Outlook 2003 last August, preferring to wait until Outlook 2007 was ready. So we've got about 250 faculty and academic staff, plus 1800 students, using the web interface exclusively.

There are latency issues and browser and ZWC bugs, some of them new to 5.0 (we upgraded from 4.5.10 on January 19), making a fair number of people wish for a supported fat client. Roughly 150 long-time Mac users seem happiest with the combination of Apple Mail and the iSync connector... though the recent addition of Safari 3 support makes web browsers more attractive again. Firefox still has issues on Macs... in ZWC, we see display problems and keyboard shortcut failures (especially the delete key being ignored). On the Windows platform we have perhaps 100 users of Thunderbird or (rarely) other IMAP clients. The rest are currently using ZWC via Firefox.

We intend to roll out Outlook 2007 to about 400 administrative staff in March on the help desk's theory that they live in MS Office. Currently they are still using the GroupWise fat client.

Printing, mail-merge and other MS Office integration possibilities, sync with legacy PDAs, and the prejudice that "desktop applications are faster and more capable" are the stated reasons for preferring Outlook 2007 to the web.

We've essentially ditched Outlook (2000/2003) in favor of using the Zimbra Web Client for about 350 users. For at least right now we're still using the FOSS edition of Zimbra, which means no Outlook Connector option. So, with the FOSS edition at least, I would agree with you that the ZWC is the only way to get full functionality.

I can't say that the transition from Outlook to the ZWC has been entirely smooth. First of all, you are always going to get your users who are resistant to change. Beyond that though, as Rich pointed out, there are some bugs with the ZWC. (I'm planning on upgrading to 5.0.1 on Sunday, so I hope there aren't too many new bugs.) I wish I could convince my bosses to switch from IE to Firefox as our supported browser of choice, especially because I think the ZWC runs much better with Firefox, but as of yet I've had no luck in doing so.

I'm the #1 fan and advocate of the Zimbra web client in our company, but even I will admit that there are some things that a "fat client" like Outlook or Thunderbird do better, especially with regards to integration with Windows/Office. Not being able to do "File --> Send To --> Mail Recipient" from within Word or Excel, and not being able to select several files and drag them into an email are two of the things our users really complained about. If Zimbra could ever get those two things working with the web client I would be a very happy man.

Personally, I've switched from using a thick client to web only, and so has most of the group I work in. I've used Outlook, Thunderbird, Eudora(Yikes!), and Mac Mail and have gone back and forth between all of them....but I keep coming back to the Web client. It has all the features I need and it's the same everywhere I go. I usually use the advanced client full time while working and the basic client from home. I use a Mac and use Camino for the browser and have not had too many bugs, except for in Documents...but I think those are fixed in a later version.

We don't have a set standard of client for our users but I know most faculty/staff use a thick client and most students use web only. I know some people that have given the web client a solid try and really liked it, but went back to whatever client they were using mostly because they were used to it.

We are just preparing for the migration to Zimbra from our old system. At this time, we are recommending the web client. Then, if that doesn't work for a specific person, we will see what they need and recommend a fat client. And we have decided to go with Firefox as the browser. But we are not taking IE off...

I work in a high school and have just completed a migration to Zimbra using exclusively the web client for admin staff, teachers, external support agencies and students.

I was anticipating most resistance from the Outlook users, but they have taken to the web client remarkably well. Thumbs-up to Zimbra there for creating a highly-innovative web client - thanks!

We used to have a few Outlook and Outlook Express users (admin and headteacher); but we decided against the continuation of these for several reasons:

Reinstalling or restoring workstations meant we had to backup and restore local 2GB+ PST/DBX files each time - nightmare. We've wasted hours/days restoring these.

Open source edition, so no Outlook connector for us.

Training - all users using the same platform is easier for everyone

The Windows-based network currently has IE6 installed for all users, and we found that the web client performs much better in Firefox. To provide the best possible experience for all users I decided to push out a customised Prism webapp (the same application used to access Zimbra Desktop - a 'cut down' Firefox). This also means there's more screen real-estate for their email

To make it even easier for our users (teachers, bless them ) I created a C# application that takes advantage of the Pre-authentication feature to launch the Prism application and save them having to type their username and password. This is one less barrier to face when tempting our Outlook users away from the dark side

Sounds like we have similar problems, and solutions! We also looked at Prism, but decided that we would only push the web client. As I am responsible for the training, having one supported client is best!

The issue we face here is that our PCs are not locked down. Anyone can install and use any app. So, I can't ensure that everyone uses Firefox.

Further, we are strongly recommending training for a consistent message, but I'm not sure if we will end up with mandatory training...

Your C# app sounds wonderful. You have your authentication tied in to their desktop. We aren't there yet... Working on it!